In 1995, with American lawmakers having failed to agree on a budget, the government shut down. As a result, President Bill Clinton found himself surrounded by interns in the White House, as regular staff had to stay home. That’s how Clinton met Monica Lewinsky.

Now, 18 years later, the federal government is shutting down again. The government needs a new loan to keep paying its bills, but Republicans will only agree to letting it borrow more money if Democrats agree to reduce Obamacare, President Obama’s government-supported national health care system. Since neither side has backed down, federal agencies are preparing to close their doors Tuesday. Employees will be furloughed – forced to stay home without pay – and only essential services will be performed.

“Essential services” is the critical word: The government doesn’t actually shut down. According to calculations by USA Today, only some 40 percent of federal workers will have to stay home. The armed forces won’t be furloughed, for example: All soldiers and officers must remain on the job, though they won’t be paid. In other words, the Afghanistan war won’t be directly affected. Firefighters assigned to federal agencies will remain on the job, too. But national parks will close, and offices processing visas and passports will operate a limited service.

Crucially, lawmakers and the president are exempt from furloughs, so they’ll keep working. They’ll be under enormous pressure from the public to get the government running again: According to a new CNN poll, 68 percent of Americans think the shutdown will be bad for the country, while 60 percent think it’s more important to keep the government running than to make changes to Obamacare. Forty-six percent blame the Republicans for the shutdown, while 36 percent blame President Obama.